If you have a Windows CD you should find that you are offered the option to completely reformat the hard disk as the setup program installs Windows. Look out for the option to either keep the existing Windows installation, or format disk.
If you want to plug in a new hard disk there are several things to watch out for. Make sure the disk is correctly set to be either the Master or Slave drive. (Read the instructions on this. You may need to change some pins on the drive. Read the instructions either supplied with the device, or on the manufacturer's website.) Once the device had been installed, right-click on your My Computer Icon. Select "Manage". Select "Disk Management". Your new device should be listed. Right-click on the device and select "Format".
O2, June 2005
